骨髓基质细胞及VLA-4抗体对儿童白血病细胞凋亡影响的研究

Effects of bone marrow stromal cells and VLA-4 antibody on apoptosis of childhood leukemia cells

目的研究骨髓基质细胞(BMSCs)对儿童白血病细胞的保护作用及细胞粘附分子缓慢抗原-4(VLA-4)抗体对原代白血病细胞凋亡的影响。方法分离儿童白血病骨髓单个核细胞,培养BMSCs及白血病细胞。实验分4个组:①白血病细胞单独培养组(对照组);②BMSCs+白血病细胞组(BMSCs组);③BMSCs上清+白血病细胞组(上清组);④BMSCs+白血病细胞+VLA-4抗体组(抗体组)。流式细胞仪检测各组白血病细胞的凋亡率,RT-PCR方法检测各组白血病细胞survivin和bcl-2基因的表达。结果 BMSCs组和上清组的白血病细胞凋亡率均低于对照组,P<0.05。与BMSCs组和上清组比较,抗体组的凋亡率显著增高,P<0.05。抗体组12h的凋亡率与24h的凋亡率比较,差异有统计学意义,P<0.01。与BMSCs组和上清组比较,抗体组survivin、bcl-2基因的表达均有降低,P<0.05。结论 BMSCs对白血病细胞有保护作用,VLA-4抗体能够抑制白血病BMSCs与白血病细胞间的粘附,促进白血病细胞的凋亡。

Objective To study the protective effect of bone marrow stromal cells（BMSCs） upon childhood leukemia cells and the influence of VLA-4 antibody in vitro on leukemia cell apoptosis.Methods BMSCs from children with acute leukemia were isolated by human lymphocyte separation medium.BMSCs（adherent） and leukemia cells（suspended） were cultured in vitro.This study included four groups：leukemia cells alone（control）,leukemia cells＋BMSCs,leukemia cells＋BMSCs supernatant and leukemia cells＋BMSCs＋VLA-4 antibody.The apoptosis rate of leukemia cells in the four groups was determined by Annexin Ⅴ-FITC double-labeled flow cytometry.The expression of survivin and bcl-2 genes in leukemia cells was ascertained by RT-PCR.Results The apoptosis rate of leukemia cells in the leukemia cells＋BMSCs and the leukemia cells＋BMSCs supernatant groups was lower than that in the control group（P0.05）.Compared with the leukemia cells＋BMSCs and the leukemia cells＋BMSCs supernatant groups,the apoptosis rate of leukemia cells in the VLA-4 antibody group increased significantly（P0.05）.In the VLA-4 antibody group,the apoptosis rate of leukemia cells increased with prolonged culture time.There were significant differences in the apoptosis rate between 12 hrs and 24 hrs after VLA-4 antibody treatment（P0.01）.The expression of survivin and bcl-2 genes in leukemia cells from the VLA-4 antibody groups was reduced compared with that from the leukemia cells＋BMSCs and the leukemia cells＋BMSCs supernatant groups（P0.05）.Conclusions BMSCs play protective roles on leukemia cells.VLA-4 antibody can block the adhesion between BMSCs and leukemia cells and promote leukemia cell apoptosis.